Centralized traffic controlling system for railroads



W. D. HAILES Dec. 1, 1936.

CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS Filed June .29, 1952 5 Sheets-Sheet l TQM m m Tm INVENTOR W D. Hailes HIS ATTORNEY w. D. HAILES Dec. 1, 1936.

CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS Filed June 29, 1932 3 Sheets-Sh et 2 E H NE NH 00 HQ #9 fiPvTv fi E q I. u m EU .1 a d INVENTOR W, D. Hailes BY H15 ATTORNEY Dec. 1, 1936. w. D. HAIIZES CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS Filed June 29, 1932 3 Sheets-Sheet 5 INVENTOR W. D Hai Ies BY M15 ML, H15 ATTORNEY Patented Dec. 1, 1936 UNITED STATES CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS William D. Hailes, Rochester, N. Y., assignor to General Railway Signal Company, Rochester,

Application June 29, 1932, Serial No. 619,951

27 Claims.

This invention relates to centralized trafiic controlling systems for governing traffic on railroads, and more particularly pertains to the communication part of such systems.

The present invention contemplates a centralized traffic control system in which communication is established between a central control office and a large number of outlying field stations by means of a communication system of the station selective coded duplex type. In a communication system of this type, a series of impulses forming a particular code combination is transmitted over a control line circuit interconnecting the control ofiice with the outlying field stations for the selection of a particular field station and the transmission of controls to that selected station. Similarly, a series of impulses forming a particular code combination is transmitted over an indication line circuit connecting the control ofiice and the outlying field stations for the registration of a field station and the transmission of new indications from that station. These two circuits, namely, the control circuit and the indication circuit, are so interrelated by the selector type apparatus employed that controls and/or indications may be transmitted during any particular cycle of operation.

In a system where there are a large number of outlying field stations, it will be apparent that several field stations may have new indications to transmit at the same time, but suitable means are provided so that only one such station may transmit its indications during one particular operating cycle, with suitable means to restore that station to normal at rest conditions as soon as it has completed its transmitting operation.

However, it may happen for one reason or another that a field station will fail to properly register itself in the control ofiice, or even if it has transmitted its indications, that it will fail to restore itself to normal at rest conditions. In such cases, the field station would continue to initiate the system into operation and continue to endeavor to register itself in the control office, thereby interfering with the proper transmission of indications from other field stations.

In accordance with the present invention, it is proposed to provide suitable means whereby that particular field station which undesirably continues to call the control ofiice may be suppressed or prevented from calling by the manual manipulation of a suitable control device in the central control ofiice.

In previous systems of this character, means has been provided for accomplishing the suppression of a selected field station by the transmission of a control code in a similar manner as the transmission of the controls to the respective traffic governing devices which are operated from the central ofiices. reception of controls at the field station to be suppressed is essential. This application is an improvement of the system disclosedin the prior application of Hailes and De Long, Ser. No. 526,674, filed March 31, 1931.

In such systems the proper However, in the system of the present invention, the operation of the apparatus involving step-by-step operations and suitable station selections is eliminated, and it is only necessary that the control and indication linecircuits be completed throughout the system in order to suppress that field station which is continuously initiating the system into operation. More specifically, it is proposed to suppress or cut out that I particular field station dominating the indication line circuit by prolonging beyond the normal time period the first impulse of a series applied to the control line circuit, so as to operate a time responsive suppressing device at that station.

the most superior station then efiecting the in dication line, the troublesome station is eliminated.

The present invention also contemplates that a field station may have more than one group of indications to be transmitted, and that a fault or failure may occur within a particular group. In such cases, only the particular group of indications having the failure is the one which is suppressed. Such an arrangement allows the proper transmission of indications from the remaining groups of indications at that station.

Other features of the present invention reside in the various circuit arrangements particularly adaptable to systems of this type.

These characteristic features of the present invention, thus briefly stated, will be explained more in detail in the following description of one embodiment of the invention; and various other features, functions and advantages of a system embodying this invention will be in part pointed out and in part apparent as the description thereof progresses.

In describing the invention in detail, reference will be made to the accompanying drawings, in which those parts having similar features and functions are designated throughout the several views by like letter reference characters that are generally made distinctive either by reason of distinctive exponents representative of their location, or by reason of preceding numerals representative of the order of their operation, and in which:-

Fig. 1 illustrates the apparatus and circuit arrangements employed at a typical control oifice of a centralized traific control system embodying the present invention; and

Figs. 2 and 3, when considered together (as hereinafter explained) illustrate the apparatus and circuit arrangements employed at a typical field station of a centralized traffic control system embodying the present invention.

For the purpose of simplifying the illustration and facilitating in the explanation, the various parts and circuits constituting the embodiment of the invention have been shown diagrammatically and certain conventional illustrations have been employed, the-drawings having been made more with the purpose of making it easy to understand the principles and mode of operation, than with the idea of illustrating the specific construction and arrangement of parts that would be employed in practice, Thus, the various relays and their contacts are illustrated in a conventional manner, and symbols are used to indicate connections to the terminals of batteries, or other sources of electric current, instead of showing all of the wiring connections to these terminals.

The symbols and are employed to indicate the positive and negative terminals re spectively of suitable batteries, or other sources of direct current; and the circuits with which these symbols are used, always have current flowing in the same direction. The symbols (3+) and (B) indicate connections to the opposite terminals of a suitable battery, or other direct current source which has a central or intermediate tap designated (CN) and the circuits with which these symbols are used, may have current fiowing in one direction or the other depending upon the particular terminal used in combination with the intermediate tap (CN). When alternating current is used in place of direct current, the particular symbols employed represent relative instantaneous polarities.

Although the present invention may be considered as an adjunct applicable to and usable with any type of communication system, it is considered expedient to explain and disclose in ageneral manner the application of the present invention to a typical selective type communication system, such as shown for example, in the pending application of Thomas J. Judge, Ser. No. 613,353 filed May 25, 1932, to which the present invention has been more particularly adapted. However, the present invention is to be considered as usable with any other selector type of communication system. Thus, in considering the structure and mode of operation of the present embodiment, it becomes necessary to explain some of the features of the communication system, insofar as material to an understanding of the present invention, reference being made to said prior application for other details of the structure and operation not directly related to the features of this invention.

Communication system generaZZy.The general plan of organization of a centralized traffic controlling system embodying the present invention provides a central control o-ffice interconnected with a large number of outlying field stations by three line wires, namely, a control line wire I0, an indication line wire l2, and a common return line wire M. The control line wire l9 and the common return line Wire M are connected only at the end field station, so as to make up a control line circuit extending through the several stations which is supplied with energy from a control battery CB in the control oifice. Similarly, the indication line wire l2 in combination with the common return line wire l4 makes up an indication line circuit supplied with energy from an indication battery IB in the control o-fiice. However, the indication line wire I2 is open ended at the last field station and the indication line circuit is completed by connecting line wire l2 to the common return wire M at the particular station selected for the transmission of indications.

With reference to Fig. 1, a typical control office has been illustrated, and similarly with reference to Fig. 2, a typical field station has been in part illustrated, it being understood that there are a large number of similar field stations, which, when placed end to end, go to make up a complete system.

Thus, with reference to Figs. 1 and 2, it will be seen that the control line circuit includes in the control line wire H) a three position biasedto-neutral polar line relay F (with suitable exponents) at the control office and at each of the field stations. In the control oifice, a polarity determining relay D of the three position biasedto-neutral polarized type has suitable pole changing contacts l6 and I! included in the control line circuit to determine the polarity of impulses impressed thereon; while an impulsing relay E includes a back contact H? for periodically opening the control line circuit to determine the time spaces between successive impulses.

The indication line circuit includes a message relay ME in the control ofiice together with the indication battery IB in series therewith; while at the field stations a back contact l9 of the look-out relay LO of that station is included therein to determine whether the indication line circuit should pass on to other field stations or be connected to the common return line. Each field station includes a resistance R for compensating for the difference in distance between the several field stations and the control office.

Control ojfice equipment-The control office equipment includes besides the apparatus directly associated with the line circuits, as mentioned, a quick acting line repeating relay FP which repeats each energized and each deenergized condition of the line relay F.

A slow acting line repeating relay SA, is provided to mark off the cycles of operation by being picked up at the beginning of a series of impulses and being dropped at the end of such series. In order to do this the relay SA is provided with such slow acting characteristics that it is slow in picking up thereby requiring a long impulse at the beginning of a series of impulses but is relatively slower in releasing so that its contacts are maintained in picked up positions during the time spaces between successive impulses of the series until the relay has been deenergized for a predetermined period of time at the end of such series of impulses. Associated with the relay SA is a repeating relay SAP which is provided with slow acting characteristics similar to those for relay SA.

The impulses of a cycle of operation, as repeated by the quick acting line repeating relay FP, cause the step-by-step operation of a step relay bank including relays IV, 2V and 3V, together with a half-step relay VP. This stepping relay bank is arranged to take one step for each deenergized condition of the control line circuit between succeeding impulses of a cycle.

An impulsing relay E is associated with the stepping relay bank in order to time space the impulses on the control line circuit in accordance with the actual response of the system.

The control office includes, besides the selector type apparatus, a suitable control machine having a group of control levers for each of the outlying field stations, a miniature track diagram corresponding to the layout in the field, and various indicating lamps or equivalent devices for indicating the condition of the operated devices and the position of trains along the trackway. That part of the control ofiice illustrated in Fig. 1 more particularly illustrates that part of a control machine associated with a single field station having a single track switch, a cross-over or the like.

This apparatus for one track switch comprises a switch machine control lever SML, a signal control lever SGL, a miniature track switch ts and a track occupancy indicating lamp OS.

The movement of the switch machine control lever SML from one extreme condition to the other followed by the actuation of the starting button SB causes the operation of the corresponding track switch in the field by the proper transmission of a control through the medium of the communication system. The momentary actuation of the starting button SE is preferably stored by a suitable relay (not shown) which then picks up a corresponding code determining relay CD for the associated station. Such control has been merely indicated in order to simplify the present disclosure.

Associated with each code determining relay CD is a group of code jumpers arranged in a manner to cause the system to transmit a code call for selecting the field station associated with that particular code determining relay whenever they are rendered effective by the energization of the code determining relay CD.

Also, associated with each field station is a group of indication storing relays of the two position magnetic stick type, such for example, as relay IR, which relays are rendered controllable during a cycle of operation when the corresponding field station has registered itself in the control office by the energization of its corresponding station relay ST. An indicator lamp is preferably provided for each station relay, such as indicator lamp 8 for relay ST, to inform the operator when the corresponding station is registered.

A control omce starting and cycle controlling relay C is provided to initiate the system into operation whenever it is energized while the system is at rest. Although this starting relay C is usually controlled by the storing relays associated with the several starting buttons SB for the field stations, it is considered sufiicient for a disclosure of the present invention to merely indicate that the starting relay is controlled by the starting button SB. 7

Whenever a field station has new indications to transmit, it closes the indication line circuit while the system is at rest which results in the energization of a field starting and cycle' controlling relay FC.

A cut-out button COB is located on the control panel for causing the manual suppression of any particular field station, in a manner more specifically explained hereinafter. Associated with the cut-out button COB is a storing relay S which stores the momentary actuation of this cut-out button. The actuation of the storing relay S causes a thermal time element relay TE and another storing relay 2S to become eifective to place a prolonged impulse upon the control line circuit for the manual suppression of that particular field station desired to be cut out by the operator. These relays are so inter-related with the general transmitting apparatus that they become effective to cause the suppression of a station only at the beginning of a cycle of operation, so as not to interrupt or mutilate a cycle already in progress.

- The control office includes various sources of current supply, bus wires, circuit connections, indicator lamps, terminal boards, overload protection, and such other devices which may be required for the proper functioning of a system of the type contemplated by the present invention.

Field station equipm.ent.With reference to the drawings, Fig. 2 illustrates more particularly the selector type apparatus associated with the line circuits of the communication system while Fig. 3 indicates some of the same relays together with the added apparatus employed to divide the indications of a field station into several groups having associated therewith, the apparatus provided for the suppression of a station and/or the suppression of a particular group of indications. With referenceto Fig. 3, a turn-out track is illustrated as connected to a, main track bya track switch TS, which is operated by a suitable switch machine. switch machine is governed from the control office in accordance with the position of the switch machine control lever SML in any suitable manner such as disclosed for example in the above mentioned application of T. J. Judge, Ser. No. 613,353 filed May 25, 1932.

Suitable signals M and IB are provided for governing eastbound trafiic over the main track and ontothe turn-out track respectively; while signals 2A and 2B are provided for governing westbound traffic over the main track and off the turn-out track respectively. These signals lAlB and 2A2B are assumed to be controlled in accordance with the position'of the track switch TS, and in accordance with suitable automatic signalling subject to the control of the op' erator by the position of the signal control lever SGL in the control oflice, which for the sake of simplicity, has been omitted.

A detector track section of the closed track circuit type is associated with the track switch TS and includes the usual battery and a track relay T.

It is assumed that several track switches and their associated signals, and the like, are located at this field station and may have indications to transmit the same as the track relay T, for example, but for convenience in illustration, such additional traflic controlling devices have been omitted. It is sufiicient for an understanding It is contemplated that, thisof the present invention to know, that, with each group of devices making up what may be termed an indication station, suitable devices are employed to give a preference or a relative superiority to such groups of devices.

For example, a change relay ZCH, a lock relay 2L and a suppression relay ZSU are associated with the traific governing devices having indications to transmit which make up the indication station associated with the track switch TS; while the corresponding relays ICH, IL, and ISU are considered to be associated with another group of devices of indications.

The communication part of the system includes, besides the apparatus already mentioned, a quick acting line repeating relay FP which repeats each energized and each deenergized condition of the line relay F (see Fig. 2). Also, a slow acting relay SA is employed to mark off the cycles of operation by being picked up at the beginning of a cycle of operation by the first impulse, and by being dropped at the end of such cycle a predetermined time after the removal of the last impulse of that cycle.

A field station includes a bank of stepping relays IV 2V and 3V together with a half-step relay V'P which are controlled in a manner similar to the stepping relay bank in the control office and need not be disclosed in detail.

Associated with the relay 5A is a quick acting repeating relay SAP provided to cause the positive operation of the system, as later to be explained.

A lock-out relay L0 is provided to register at the field station, when that field station is the most superior one having indications ready to transmit; and similarly, a relay S0 is provided to register at the field station when that field station is selected for the transmission of controls thereto.

For the purpose of governing the indication line circuit, a pulsing relay PL is provided to operate in accordance with the indication contacts of that particular group of indications selected by the lock relays L (with suitable preceding numerals) on the several steps of a cycle, as marked off by the stepping relay bank.

A signals-at-stop relay SR is provided to be controlled in accordance with the position of the signal lever SGL in the control office. Whenever the signal lever SGL is placed in a central at stop position followed by the actuation of the starting button SE, a stop control is transmitted and the relay SR is momentarily picked up. Such momentary opening of the back contact of relay SR, causes all of the associated signals lAlB and 2A-2B to give stop indications which is sufficient for an understanding of the present invention, but which has been completely disclosed in the pending application of N. D. Preston, Ser. No. 573,079 filed Nov. 5, 1931.

A lock stick relay LSR (see Fig. 3) is so associated with the lock relays L (with suitable preceding numerals) that whenever a lock relay L is stuck up, a succeeding change in some other group can not pick up another look relay until the one already up is deenergized, which provides a positive acting interlock arrangement.

A time element relay TE of the thermal type together with a storing stick relay 2S is provided to measure oil a period of time during each initiation of the system effected by the associated station, so that if the first impulse of a cycle of operation exists for more than the period of time measured by relay TE the suppression of a field station is accomplished.

The field station also includes suitable bus wires, circuit connections, code jumpers, overload devices and other devices necessary for a communication system and a centralized traffic control system as contemplated by the present invention.

It is believed that the nature of the invention, its advantages and characteristic features can be best understood by setting forth further description from the standpoint of operation.

Operation The system of the present invention is normally in a condition of rest, but may be initiated into a cycle of operation either from the control ofiice or from any of the field stations whenever there are new controls or new indications ready to be transmitted. If new controls for several different field stations are ready for transmission at substantially the same time, the controls for the several stations are transmitted on separate cycles of operation, one station for each such cycle. Similarly, if several field stations have indications ready for transmission at substantially the same time, the indications are transmitted from such field stations to the control ofilce, one station at a time on separate operating cycles.

It may happen that there are new controls and new indications ready to be transmitted at the same time, and in such instances controls are transmitted to a selected field station, and simultaneously therewith indications are transmitted from that field station or some other field station during the same cycle of operation.

Irrespective of whether a cycle of operation is to be for the transmission of controls and/or the transmission of indications, a predetermined number of impulses are placed upon the control line circuit to accomplish the step-by-step operation of the stepping relay banks. These impulses placed upon the control line circuit are time spaced, that is, the impulses follow each other at definite time intervals. That period of time during which the control line circuit is energized with an impulse is conveniently termed an executing period, while the deenergized period of the control line circuit between successive impulses is conveniently termed a conditioning period. Also, for convenience in describing the present invention, the normal condition of the system between successive cycles of operation is conveniently termed a condition of rest.

When a cycle of operation is initiated for the transmission of controls, the character of the plurality of impulses placed upon the control line circuit is determined in accordance with the code call of the station to be selected and in accordance with the controls to be transmitted, as set up by the code jumpers and control levers for that station. On the other hand, during a cycle of operation initiated for the transmission of indications alone, the character of the plurality of impulses placed upon the control line circuit is such as to fail to select any station, but merely to cause the step-by-step operation of the stepping relay bank at the control ofiice and at the particular field station having indications to transmit.

When a cycle of operation is initiated from a field station for the transmission of indications, the control line circuit is impulsed either for the transmission of controls or with a non-selecting code call, during which the indication line circuit is pulsed for the transmission of indications. In other words, on each step taken by the step-bystep mechanism at the field station the indication line circuit is either opened or closed in accordance with the position of the indication contact for that step. Such conditions transmitted to the control ofiice are rendered effective to position on the corresponding steps suitable indication storing relays.

It is considered advisable to explain in general the operation of the communication parts of such a system in order to give the cooperating links or features between such parts and the present invention, and to also show its adaptability to a suitable communication system, such as shown for example in the pending application of T. J. Judge, Ser. No. 613,353 filed May 25, 1932.

Normal at rest conditions.Although the system may be initiated from the field stations, the

line circuits are normally deenergized and similarly, the remaining circuits of the system are arranged to be normally deenergized with a few I exceptions.

The change storing relays at the field stations (such as relays ICE and 20H for example) are provided with normally closed stick circuits, so as to insure the registration of a change when there are a plurality of devices having change contacts "included in the control circuits of a single change relay, all of which has been disclosed in the patent of D. F. De Long et al., Pat. No. 1,852,402 dated April 5, 1932.

For example, the relay 2CI-I (see Fig. 3) is normally energized by a circuit closed from ed into a cycle of operation for the transmission of controls. Whenever such a cycle of operation is desired, the operator first positions the control levers for the field station or stations, which he desires to control, and then actuates the associated starting button or buttons to cause the transmission of the control conditions thus set up.

Whenever the starting button for a station is actuated, such actuation is suitably stored or registered in a suitable relay (not shown) irrespective of whether the system is at rest or is progressing through a cycle of operation. If the system is at rest, the corresponding code determining relay, such as relay CD for example, is immediately picked up; but, if the system is already in operation, and some other code determining relay is picked up, then the code determining relay associated with that starting button just actuated is picked up in turn in accordance with its location in the bank of code determining relays.

-in detail, as it is believed to be sufiicient for an understanding of the present invention to know that the relay CD (see Fig. 1) is picked up, when the system is at rest, in response to the actuation of the starting button SB if there is no other code determining relay picked up. Such an interlocked bank of code determining relays has been shown in detail in the pending application of N. D. Preston et al., Ser. No. 455,304, filed May 24, 1930, corresponding to the Australian Patent 1501 of 1931.

Also, the actuation of the starting button SB usually effects the energization of the control office starting and cycle. controlling relay C through the medium of its corresponding storing relay (not shown), but for the purpose of the present disclosure it is considered sufficient to illustrate the relay C as being directly energized by the starting button SB. Thus, with the system at rest, the actuation of SB closes a pick-up circuit from through a circuit including back contact 23 of the quick acting line repeating relay FP, back contact 24 of relay SAP,- upper winding of relay C, back point of starting button SB, to As soon as the contacts of the relay C respond to this energization of its pick-up circuit, a stick circuit is closed from through a circuit including back contact 25 of relay SAP, lower winding of relay C, front contact 26 of relay C, to

This energization of the relay C with the system at rest prepares a circuit for the relay D to be energized on each step with a polarity in accordance with the respective code jumper or control lever for that step as selected by the relay CD.

Polarity selection.--The closure of front contact 21 of the relay C with the relay CD already picked up closes an energizing circuit for the relay D either from (3+) or (B through a circuit including code jumper 28 either in an upper or a lower position respectively, front contact 29 of the relay CD, code bus 30, back contact 3| of relay IV, back contact 32 of relay 2V, back contact 33 of relay 3V, front contact 21 of relay C, windings of the relay D, to (CN). This energization of the relay D with positive or negative potential depending upon the position of code jumper 28 actuates its contacts to right or left hand positions for applying positive or negative potential to the control line circuit from the control battery CB.

For example, with the code jumper 28 in the position illustrated, the control line circuit is closed from the positive terminal of the control battery CB, through a circuit including polarcontact I6 of relay D in a right-hand position, back contact I8 of relay E, windings of the line relay F, through the control line wire II] to the first field station, windings of the line relay F at the first field station, and similarly through the remaining field stations over the control line wire In to the end of the system where connection is made to the common return wire I4, and thence tothe control ofiice through the several field stations, polar contact I! of the relay D in a right-hand position, to the negative terminal of the control battery CB.

As the front contact 21 of relay C is maintained closed throughout the cycle of operation, the energization of the relay D will be dependent upon the position of the code jumper 34 upon the picking up of the contacts of the stepping relay IV, by reason of a circuit including front contact 3I of relay IV, and front contact 35 of relay CD.

In a similar manner, the picking up of the contacts of the relay 2V transfers the energization 75'.

closurof the front contacts of the relay VP o'mpletes an energlzmg clrcult for the 1mp 1 the relay FP, the next stepping relay 2V is energized through its pick-up circuit closed from through a circuit including front contact 55 of relay SA, back contact 56 of relay FP, back contact 51 of relay VP, back contact 5! of relay 3V, front contact 62 of relay IV, windings of relay 2V to As soon as the contacts of the relay 2V have responded to this energization, a stick circuit is closed from through a circuit including front contact 55 of relay SA, front contact 63 of relay 2V, windings of relay 2V, to

The picking up of the contacts of the relay 2V opens the energizing circuit of the relay E at the back contact 53, but the relay D is energized with a polarity in accordance with the position of contact 36 of the switch control lever SML, and the contacts l6 and Il assume their energized positions, before the back contact of the relay l8 closes.

This energization of the control line circuit is repeated by the relays F and FP. The picking up of the contacts of the relay FP closes a pickup circuit for the relay VP from through a circuit including front contact 44 of relay SA, front contact 45 of relay FP, back contact 46 of relay 3V, front contact 4'! of relay 2V, lower winding of relay VP, to As soon as the contacts of the relay VP assume picked up positions, a stick circuit is closed including front contacts 49 and 56 of the relays SA and VP respectively, as previously pointed out.

The response of the relay VP closes an energizing circuit for the relay E from through a circuit including front contact 5| of relay VP, lower winding of relay E, front contact 53 of relay 2V, back contact 54 of relay 3V, to

The response of the relay E deenergizes the control line circuit which is repeated by the relays F and PP.

The closure of the back contacts of the relay FP closes a pick-up circuit for the relay 3V from through a circuit including front contact 55 of relay SA, back contact 56 of relay FP, front contact 51 of relay VP, front contact 58 of relay 2V, windings of relay 3V, to As soon as the contacts of the relay 3V respond, a stick circuit is closed from through a circuit including front contact 55 of relay SA, front contact 64 of relay 3V, to

The picking up of the contacts of the relay 3V opens the energizing circuit of the relay E, and connects the relay D to the contact 31 operated by the signal control lever SGL. Thus, the control line circuit is energized upon the closure of back contact [8 in accordance with the polarity of the signal lever SGL, and this impulse is repeated by the relays F and FP.

The picking up of the contacts of the relay FP closes a differential energizing circuit for the relay VP from through a circuit including front contact 44 of relay SA, front contact 45 of relay FP, front contact 46 of relay 3V, front contact 66 of relay VP, upper winding of relay VP, to This causes the contacts of the relay VP to drop away, as previously explained.

Although only three steps have been illustrated, it is to be understood that any number of the relays F, FP, SA, VP and E; while the energization of the control line circuit for'the succeeding impulses of a cycle of operation includes the pick-up times of the relays F, FP, and E together with the proper positioning of the relay VP. On the other hand, the duration of the deenergized period between successive impulses includes the drop-away time of the relays F and FF, the pick-up time of the relay IV, and the drop-away time of the relay E.

At the field station the application of the first impulse of the cycle to the control line circuit is repeated by the relays F FP and SA in a similar manner as explained for the relays F, FPand SA in the control office. The circuits will be obvious from the drawings.

Also, the stepping relay bank, including relays lV 2V and 3V together with the half step relay VP operates in response to the relay FP in a step-by-step fashion similar to that explained for the stepping relay bank in the control ofiice, and for this reason it is considered that such operation need not be explained in detail. It is to be understood in this connection, however, that the step-by-step operation at the field stations may be made dependent upon the effective station selection or registration so as to save relay operations, but it is unnecessary to consider such refinements in a disclosure of the present invention. It is sufficient for an understanding of the present invention to know that the step-by-step operation occurs whenever a field station receives controls or transmits indications. Such selective control of the stepping relay banks at the field stations is completely disclosed in the above mentioned application of T. Judge, Ser. No. 613,353 filed May 25, 1932.

Station selection and reception of controls. The manner in which the control line circuit receives impulses of selected polarities has been explained, and now the response of the field station to these distinctive impulses will be considered. In the ease assumed, only controls are being transmitted from the central office and the indication part of the system need not be considered at this time.

The polarities of the first two impulses applied to the control line circuit are determined in accordance with the positions of the code jumpers 28 and 34. It is obvious that these code jumpers may be so positioned so as to form any one of four different code combinations, and the impulses of that particular code combination applied to the control line circuit during a cycle are repeated by the line relays F (with suitable exponents) at the control office and at the field stations. Suitable code responsive means is provided at each field station to respond to one particular code combination for the selection of its station.

For the purpose of illustration, a station selecting relay SO (see Fig. 2) has been indicated as controlled by the first two impulses of a cycle over two local channel circuits, and it is assumed that this relay S0 is responsive to one particular code combination, as for example which code call is set up by the code jumpers 28 and 34 When-in the positions illustrated. The control of the relay SO need not be disclosed in detail, as such control may be accomplished in any suitable manner such as disclosed for example in the pending application of N. D. Preston et al., Ser. No. 455,304, filed May 24, 1930.

After the station is selected, the next impulse to the control line circuit is: effective to position suitable storing relays for governing their respective trafi'ic governing devices at that field station. These storing relays (not shown) for governing the traffic controlling devices are usually twoposition magnetic stick type relays or their equivalent, so as to remain in their last operated positions as determined by the distinctive polar im pulse transmitted thereto. It is to be understood that any number of steps may be employed for controlling from the control oifice a corresponding number of these function controlling storing relays (not shown).

Included among these function controlling relays is a signals-at-stop relay, such as relay SR for example. The signals-atstop relay SR is illustrated as being controlled by the character of the impulse on the third step, or the fourth impulse of the cycle. If this impulse is positive in character, the relay SR will be energized during the application of such impulse to the control line circuit by reason of a circuit closed from (B+) through a circuit including polar contact 66 of relay F in a right-hand position, front contact 61 of relay FP front contact 68 of relay 3V front contact 69 of relay SO, windings of relay SR, to (B) On the other hand, if this fourth impulse applied to the control line circuit is negative in character, the polar contact of the line relay F is actuated to a left-hand position which applies negative potential (B) to the channel circuit for the relay SR. As the same potential is in this case applied to both terminals of its winding, the relay SR remains deenergized.

The particular character of this fourth impulse is determined by the position of the signal lever SGL. For example. whenever the lever SGL is in a center stop position the fourth impulse is caused to be positive in character resulting in the energization of the relay SR; but whenever the relay SGL is in a right or left hand clearing position, this fourth impulse is caused to be a negative impulse and the relay SR is not actuated.

The momentary picking up of the relay SR is employed for causing the signals lAlB and 2A2B to be put to stop by the opening of back contact 20, which has been merely indicated by a legend on the drawings. Also, the opening of back contact I62 of the relay SR is employed to effect the restoration or non-suppression of the field station or a particular group at the field station, as later explained.

In a similar manner, any number of additional steps may be provided for transmitting additional controls to this field station for governing the signals and such other devices as may be necessary.

End of operating cycZe.Upon the application of the fourth impulse to the control line circuit (the last impulse of the cycle) the half-step relay VP (see Fig. 1) in the control office is deenergized. This closes a pick-up circuit for the impulsing relay E from through a circuit including back contact 5! of relay VP, upper winding of relay E, front contact 54 of relay 3V, to The energization of the relay E opens the control line circuit which is repeated by the relays F and FF as during a cycle of operation. But as the last stepping relay (3V in this case) is picked up, and there are no other stepping relays to be picked up, the relay E remains energized through this circuit just traced.

After a. predetermined period of time the slow acting relay SA drops away which deenergizes the stepping relays together with the cycle controlling relay C. Following the deenergization of the stepping relays, the relay E is deenergized and its contacts drop away closing back contact I8. However, during the time that the relay E is dropping away, the relay D assumes its biasedto-neutral deenergized position, and has plenty of time to do so by reason of its quick acting polarized structure. Thus, the control line circuit is caused to remain deenergized until another cycle of operation.

This continued deenergization of the control line circuit is sufliciently long to allow the relay SA (with suitable exponent) at each of the field stations to drop away, which in turn causes the corresponding stepping relay bank and other relays at each station to be restored to normal.

In the control oifice, that particular code determining relay effective for the last cycle of operation is deenergized at the end of the last impulse applied to the control line circuit, so that if some other code determining relay is energized, it may be effective at the beginning of the next cycle of operation, assuming of course that its corresponding starting button SB has been actuated.

However, it is to be noted, that the actuation of another starting button or the same starting button, or perhaps the stored actuation of a starting button, cannot be effective to energize the starting and cycle controlling relay C until the slow acting relay SAP has assumed its deenergized position by reason of back contact 24. Also, if a field station has new indications to transmit, it cannot initiate the system until the relay SAP has dropped away for reasons pointed out hereinafter. In other words, the relays SA and SAP prolong the deenergized condition of the control line circuit at the end of a cycle to provide sufficient margin to assure that all field stations return to the normal at rest conditions before another cycle of operation is initiated. 7

Transmission of indications. The selection of field stations for out-going controls and the transmission of controls to a selected station is accomplished, as briefly explained above, over the control line circuit; while the transmission of indications is accomplished over the message or indication line circuit following the proper registration of a particular field station.

Although the system contemplated by the present invention is therefore of the coded duplex type, and indications may be transmitted from any station to the control office simultaneously and during the same operating cycle that controls are transmitted to the same or some other station, it is convenient to first consider the operation of the system for the transmission of indications alone on an operating cycle before considering the duplex feature of the system.

In a centralized traffic controlling system where there are a large number of outlying field stations for governing traffic over an extensive territory, it is obvious that trains may enter or leave track circuits at two or more points in this territory at substantially the same time, and likewise the switches and signals at the various locations may be operated from time to time in such a way that there will be indications of their operated conditions to be transmitted to the control ofiice at substantially the same time. Thus, it will be evident that some means must be employed to prevent more than one field station from transmitting over the indication line circuit at any one time. To accomplish this feature, suitable lockout means is associated with each field station which allows the field stations to transmit indicaof devices at a particular field station are divided into groups or what has been termed indication stations, it is necessary to provide some means to allow only one group of indications to be transmitted from that associated field station, when that field station or location is the superior one among the several different field stations and is allowed to transmit. This interlock between the groups of indications at a field station is accomplished by a suitable interlocked bank of relays including a change relay CH and a lock relay L for each of the groups.

As the field station illustrated in Figs. 2 and 3 is considered as one having a large number of devices to be indicated, these devices are divided in two groups. It is considered expedient to first explain the transmission of indications from a single field station and the look-out between the field stations followed by a description of the sequence between groups at a particular field station.

Automatic startinq.When a train enters the detector track section associated with the track switch TS, thereby causing the dee'nergizatio-n of the track relay T, the normally closed stick circuit of the relay ZCH is momentarily opened in the movement of contact 2| of the track relay T from a front point to a back point; and similarly, when a train passes oil the detector track section resulting in the energization of the track relay T, the stick circuit of relay 'ZCH is momentarily opened in the movement of contact 2| from a back point to a front point. It is also to be understood that a large number of devices may also have contacts for momentarily opening this stick circuit of relay 20H, but such'devices for convenience and simplicity have been omitted.

In any case, the momentary deenergization of the relay ZCH causes its contacts to drop away, and with the system in a condition of rest, a pickup circuit is completed for the lock relay 2L. This pick-up circuit is closed from (-1-), through a circuit including back contact 15 of relay SAP back contact 16 of relay 3V back contact ll of relay LSR, front contact 18 of change relay ICH, back contact 19 of change relay 20H, back contact 89 of relay 2SU, upper winding of lock relay 2L, to

As soon as the contacts of the lock relay 2L assume picked up positions, a stick circuit is completed from through back contacts 81, 92 and 83 of relays LO, VP and 3V respectively in multiple, winding of relay LSR, back contact 84 of lock relay IL, front contact 85 of lock relay 2L, back contact 86 of suppression relay ZSU, lower winding of lock relay 2L, to

From this it will be seen that the lock relay 2L will remain energized through its stick circuit until after the transmission of indications from that group, by reason of the fact that this stick circuit receives energy until the lock-out relay L0 is energized for rendering the station efiective for the transmission of indications, and until the end of the last impulse of such cycle upon which relay LO has been rendered effective, as indicated by the picking up of the relays 3V and VP.

With the system at rest, the picking up of the contacts of the relay 2L also closes a pick-up cir- Quit for the relay LO from through a circuit;

including back contact 81 of relay FP (see Fig. 2), back contact 88 of relay SAP back contact 89 of relay SA upper winding of lock-out relay LO, front contact 9|] of lock relay 2L, to It will be readily apparent that the closure o1 front contact 9| of lock relay IL in place of the contact 90 of lock relay 2L similarly'closesthe pick-up circuit for the relay L0.

The closure offront contact [9 of relay LO closes the indication-line circuit to energize the message relay ME in the control ofiice.- For example, this energizing circuit for relay ME is closedfrom the positive terminal of the indication battery IB (see Fig. 1), through a circuit ineluding the windings of relay ME, -indication-line wire H. to the first field station; front Contact 19 of lock-out relay LO, back contact 92 of relay SAP lower winding of lock-outrelay LO, compensating resistance R, through the common-re turn wire M to the control ofice; to the negative terminal of the indicationbattery IB."- e

The response ofthe relay ME closes a pick-up circuit for the field starting and cycle controlling relay F0 from (-1-), through a circuit including back'contact 93 of relay SAP, front contact'94 of relay ME, upper Winding of relay FC, to

The picking up of the contacts "of the field starting and cycle controlling relay FC prepares its stick circuit atfront contact 96, and closes an energizing circuit for the relay D at front contact 97. This energizing circuit for 'therelay D is closed from (B-), through a circuit including front contact 91 of relay FC, back contact 2'! of relay C, windings of the relay D, to (CN) This 7 energization of the relay D actuat'es" its polar contacts l6 and I! to left-hand positions, thereby applying negative potential to the control line circuit which is repeated by the line relays F (with suitable exponents) at the control oficeand at each of the field stations.

At the field station this first impulse is repeated by the relay FP which opens the pick-up circuit for the look-out relay LO, but the look-out relay 1.0 at this field station remains energized by reason of the energization of its lower winding included in the indication line circuit,"

However, should the look-out relay at some other field station farther from-the control olfice be energized through its pick-up circuit, it would drop out as soon as the relay "(with suitable exponent) at that field station is energized, because such lock-out relay cannot befenergized over the indication line circuit, as theback contact IQ of the. relay LO at the first field station is opened. In other words, during the time follow- 'ing the picking up 'of the relays FP ,(withsuitable exponents) at the several field stations and prior to the picking up of the relays SA (With'suitable exponents) at the several field stations, the lockout relays at all field stations are dropped out except that station nearest thecontrol ofiice having new indications to transmit. At such station nearest the control office( the first field station in this case, see Fig. 2) the lock-out relay LQ is maintained picked up after the response of therelay SA by a suitable stick circuit. For examme, the relay L0 is energized by a circuit closed from through a circuit including front contact 98 of relay LO, front contact 89 of relay SA pper winding of relayLQ, front contact 99 of relay L0, to 1 The closure of front contact llll of the relay 'SA energizes the relay SAP through a circuit obvious from the drawings, and as soon as its contacts respond. a stick circuit is closed fromi I02 of relay LO, front contact I03 of relay SAP windings of relay SAP to This stick circuit for the relay SAP is of course effective only at the end of the cycle, as later explained.

The opening of back contact 92 and closure of front contact 92 of relay SAP causes the indication line circuit to be conditioned in accordance with the position of contact I04 of relay PL. This contact I04 of relay PL will be opened until the first stepping relay IV is picked up, at which time it is conditioned in accordance with the first code impulse. Thus, the relay ME in the control ofilce will be deenergized until the first stepping relay is picked up which opens the pickup circuit of the relay FC. However, the picking up of the relay SA in the control oflice occurs prior to the picking up of the relay SAP at the field station, so that the relay F is maintained by a stick circuit closed from through a circuit including front contact 95 of relay SA, front contact 96 of relay FC, lower winding of relay FC, to

Also, the picking up of the relay SA followed by the picking up of the relay VP and the relay E causes the end of the first impulse, as previously described. It is unnecessary to further point out the impulsing operation, as the control line circuit is alternately energized and deenergized, and the stepping relay banks take one step for each deenergized condition of the control line circuit. It may be noted, however, that the polarity of these impulses, assuming of course that there are no controls being transmitted, is negative for each impulse of the cycle, as the control of the relay D is made dependent upon front contact 91 of relay FC-instead of the control jumpers and control levers selected by the stepping relay bank during a control cycle of operation.

The station selecting means at each field station, including relay S0, is arranged to be unresponsive or ineffective to select any field station when all negative impulses are placed on the control line circuit during a cycle of operation. However, these negative impulses cause the step-by-step operation at the field station transmitting indicationswhich in this case is the first field station illustrated in Figs. 2 and 3.

Registration of a field staticm.The picking up of the first stepping relay I V conditions the relay PL in accordance with the position of the first code jumper of the group of indications then transmitting (see Fig. 3). For example, with code jumper l05 in a contacting position, the relay PL is energized from through a circuit ineluding code jumper I05, front contact I06 of lock relay 2L, bus wire I01, front contact I08 of relay IV back contact I09 of relay2V back contact H0 of relay 3V front contact III of relay LO, windings of relay PL, to On the other hand, if the code jumper I05 is in anon-contacting position, the relay PL remains deenergized for the first step.

With the relay PL energized, the indication line circuit is closed through'the front contact I9 of relay LO (see Fig. 2), front contact 92 of relai SAP front contact I04 of relay PL, compensating resistance R, to the common return line I4; while, if the relay PL is left deenergized, the indication line circuit will likewise remain deemergized. In the control omce the particular energized or deenergized condition of the indication line circuit is repeated by the message relay ME.

Similarly, the relay PL is conditioned on the r through a circuit including front contact second step in accordance with the second code jumper II2, which is relayed on to the control ofiice for positioning the relay ME. This conditioning of the relay ME for each step may be carried on for as many steps as may be necessary to transmit the code call associated with the indication station having indications to transmit.

The condition of the relay ME on each step is stored in suitable relays for selectively energizing a station registering relay corresponding to the indication station at the particular location or field station then transmitting for the cycle of operation in progress. Such station registration is accomplished in the control ofiice by a suitable pilot relay bank arranged to decode the combinations placed upon the indication line circuit. It is considered unnecessary to disclose this feature of the system for an understanding of the present invention, and the station relay ST has been merely indicated as selectively energized on the first two steps of the operating cycle. Such transmission of a code call for the registration of a field station has been explained in detail in the above mentioned application of N. D. Preston et al., Ser. No. 455,304, filed May 24, 1930.

It should be noted in this connection, that the code call formed by the continued deenergization of the indication line circuit during a control cycle alone is not employed to select any station relay, such as relay ST for example.

Transmission of indications.--Following the registration of a field station, or an indication station at a particular field station location, the

indications at that station may be transmitted.

For example, on the third step following the registration of the second group or indication station at the field station illustrated in Figs. 2 and 3, an indication is transmitted as to the condition of the track relay T.

If the track relay T is energized for the third step the relay PL will remain deenergized; but, if the track relay T is deenergized, the relay PL will be energized by a circuit closed from through a circuit including back contact N3 of relay T, front contact II of relay 2L, bus wire H5, front contact H0 of relay 3V front contact III of relay LO, windings of relay PL, to

The positioning of the relay PL governs the indication line circuit, so as to energize the relay ME if the track relay T is deenergized, or to leave the relay ME deenergized if the track relay is picked up. It will be seen that the relay PL is conditioned as soon as the relay 3V is picked up during the third deenergized period of the control line circuit, and such condition then established is maintained throughout the following energized condition (fourth) of the control line circuit. Thus, this control of the relay ME by the relay PL is maintained during the following energization (fourth) of the control line circuit so that the condition of the relay ME will be stored or executed in the indication storing relay IR. If the relay MIE is energized, the relay IR will be energized with positive potential; but if the relay ME is deenergized it will be energized with negative potential.

More specifically, depending upon the position of the track relay T, the relay IR is energized by a circuit closed from (B+) or (B-), through a circuit including front or back contact II6 of relay ME respectively, front contact II! of relay FP, front contact N8 of relay 3V, bus wire H9, front contact I20 of station registering relay ST, windings of the relay IR, to (CN) If the relay IR is energized with negative potential, its contact IZI is actuated to a left-hand position; but, if the relay IR is energized with a positive potential, its contact IZI is actuated to a right-hand position, thereby closing an obvious energizing circuit for the track occupancy indicating lamp OS. In this way the occupied or unoccupied condition of the detector track section associated with the track switch TS is transmitted to the control oifice and displayed to the operator.

Although the transmission of but a single indication is shown, it is to be understood that any number of indications may be transmitted by the provision of additional steps.

End of operating cycZe".The system returns to its normal condition of rest at the end of an indication cycle in a similar manner as explained during the transmission of controls, insofar as the stopping of the impulsing operation is concerned. The dropping of the relay SA after the control line has been deenergized for a prede termined period of time opens the stick circuit of the relay FC at open front contact 95, which in turn deenergizes the stepping relays, and the relays D and E, so that upon the closure of back contact l8 of the relay E the control line circuit will remain deenergized.

At the field station upon the application of the last impulse to the control line circuit the relay W is picked up similarly as the relay VP is picked up in the control office. Thus, with the relays LO, VP and 3V all picked up, the stick circuit for the relay 2L is opened at back contacts 8|, 82 and 83 and the contacts of relay 2L assume dropped away positions.

However, prior to the dropping of the contacts of the relay 2L, and preferably during the first part of the operating cycle, the relay 20H is restored to a normal energized condition. This has been illustrated as occurring subsequent to the picking up of the relay IV and prior to the picking up of the relay 2V during an operating cycle, while this indication station at this field station location is transmitting, as indicated by the energization of both the look-out relay L0 and the lock relay 2L.

For example, this pick-up circuit for the relay ZCH is closed from (-1-), through a circuit including front contact 8i of relay LO, front contact I22 of relay IV back contact I23 of relay 2V front contact I24 of relay 2L, upper winding of relay 2CH, to As soon as the contacts of the relay 2CH have picked up its stick circuit is closed through front contact 22 with the track relay contact 2| in either of its positions, as previously pointed out.

The dropping of the contacts of the relay SA at the field station opens the stick circuit of the look-out relay LO at front contact 89, so that its contacts drop away closing back contact l9. The dropping away of the contact Hi2 of relay LO opens the stick circuit for the relay SAP so that its contacts can drop away allowing the initiating of the system by this field station at some subsequent time. If the contacts of the relay LO do not drop away the relay SAP will remain energized through its stick circuit and the station may not transmit indications or cause a cycle of operation to be initiated by reason of open back contact 92, all of which has been explained more in detail in the above mentioned application of T. J. Judge, Ser. No. 613,353, filed May 25, 1932.

Thus, the dropping away of the contacts of the stepping relays, and the restoration of the other relays of the field station to normal positions allows the next lock relay in sequence to: be picked up provided a change has occurred in another group of indications in a field station and the transmission of such indications will take place as just described.

Interlock between groups of indicatio=ns.-It may happen that indications in each of several groups at a field station location may occur simultaneously or in rapid succession, as previously mentioned, but only one group of indications can be allowed to transmit during any one operating cycle. To accomplish this an interlocked bank of relays, such for example as relays iL--2L and lCH2CH, are provided to determine the order in which such transmission may For example, let us assume that a change occurs in the second group as just described deenergizing relay ECI-I followed by a change in the first group deenergizing relay ICH. The deenergization of the relay 20H causes the picking up of the relay 2L, and at the closure of the stick circuit of relay 2L the relay LSR is likewise energized. If the dropping away of the contacts of the relay l CH occurs subsequent to the picking up of the contacts of the relay LSR, then the relay IL can not be picked up because of open back contact H.

'On the other hand, should the relay ICH be deenergized and close back contact '!8 prior to the opening of back contact TI of relay LSR, then the relay IL would be energized and the relay 2L would be deenergized. If the contacts of relay 2L were already picked up they would again drop because the picking up of contacts 84 of the relay lL would open the stick circuit of relay 2L and its pick-upcircuit would already be opened at front contact 18.

In brief then, the occurrence of a change in a more superior group is effective to take precedence over all other more inferior groups any time up to the opening of back contact ll of relayLSR. The picking up of any lock relay, such as relay IL, causes the initiation of the system and the transmission of the code call and indications of the associated group of indications in a similar manner as explained for the lock relay 2L.

If the sequence in which the changes occur in the two groups is reversed, so that the relay lCH is deenergized before the relay 20H, the first indication group will obtain precedence and pickup the lock relay IL, as the pick-up circuit for the lock relay 2L includes front-contact T8 of relay lCl-I. This condition is true even in the event of a simultaneous deenergization of the relays lCH and 201-1.

Although only two indication stations or groups of indications have been illustrated, it is to be understood that any number of similar groups may be employed with a similar interlock extended between all such groups. On the other hand, if there is. only enough indications for a single group, it is to be understood that only the apparatus necessary for a single group need be employed. In the event of the provision of only a single group of indications, there will be no necessity for the relay LSR and the wires P25 and 92.6 may be connected together, and similarly the back contact Ti may be eliminated from the pick-up circuit of the lock relay.

Duplex operation-4t is apparent from the above description that controls are transmitted over the control line circuit and that indications are transmitted over the indication line circuit. In both cases impulses are placed on the control line circuit. If the cycle is for the transmission of controls, these impulses are positive and negative in an order dependent upon the code combination of the desired station and the controls to be transmitted thereto; while, if the cycle is for the transmission of indications, these impulses are arranged in a non-selecting code, as for example all negative impulses. In both cases, these impulses cause the desired step-bystep operation.

In other words, when controls are to be transmitted and the relay C is picked up, indications may be also transmitted, the only difference being that in such a case the energization of the relay FC does not effect the polarity of the impulses because of open back contact 21. Thus, the impulses on the control line circuit serve the purpose of causing the stepping for both the transmission of controls and indications as well as for the actual transmission of the controls by reasonof their distinctive characters.

Manual suppression.As previously mentioned, a field station may fail to be properly restored to normal conditions at the end of a cycle, so that the system is continuously set into operation by that field station.

For example, the failure of a contact in the stick circuit of a change relay, such as relay 20H, would cause such a change relay toreturn to a deenergized condition subsequent to the momentary closure of its pick-up circuit at the beginning of a cycle of operation, as previously eX- plained. This condition would cause the picking up of its corresponding lock relay at the end of each cycle of operation, so that the system would continuously be initiated and. the transmission of the indications from the associated group of indications would be continuously placed upon the indication line circuit in preference to all the field stations farther from the control office.

In other words, the indicators of a more superior group at such a failing location or the indications from a field station nearer the control office, that is, superior by reason of its geographic location, could be properly transmitted. However, there might be important indications to be received from a more inferior group or field station location and such indications would be unobtainable by the operator Without the provision of manual suppression, as provided in the system of the present invention.

As explained above, a plurality of impulses are placed upon the control line circuit either for the transmission of controls, or for the transmission of indications, and also for a duplex cycle of operation. The first impulse of a cycle is usually slightly longer for picking up the cycle demarcating relays, such as relay SA for example.

In accordance with the present invention, additional means are provided in the control ofiice for prolonging this first impulse beyond the normal period of time, which prolongation is subject to additional manual control. Then means are provided at each field station for measuring ofi a period of time longer than the normal period of the first impulse but shorter than the prolonged period of the first impulse. In the event a field station has initiated a cycle of operation and it is the most superior station, that is, it would normally be allowed to transmit its indications, that field station is suppressed when the first impulse is prolonged which allows the operation of the time measuring device at that field station.

In other words, the time measuring device at each field station for determining when a prolonged impulse occurs is set into operation only when that field station is the one which is to transmit indications for the cycle of operation just initiated.

As long as the system operates normally and indications are properly transmitted, the operator does not actuate the cut-out or manual suppression button, such as button COB in the control ofiice, but allows the system to operate automatically. On the other hand, whenever the operator notices that a particular field station is continuously transmitting indications, he immediately actuates the cut-out button COB and the first impulse of the next cycle of operation is prolonged and causes that station to be cut out or suppressed.

For example, let us assume that for one reason or another, the change relay 2CI-I does not properly restore during an indication cycle of operation, which causes the system to thereby be continuously initiated and operated to transmit the indications from that group. This of course assumes that there are no changes in the indication conditions of the first group of the station and that there are no changes in the conditions of the indications at a more superior field station.

The continual selection or registration of this station in the control ofiice is indicated to the operator by the illumination of the station indicator lamp 8, which is energized each time the station is registered upon the picking up of the station relay ST and the closure of front contact [30.

In other words, for each indication station there is a corresponding station relay, such as relay ST, in the control ofiioe and suitable indicator means, such as indicator 8, associated with the station relays, so that when a station is registered for a large number of cycles, the operator may readily ascertain which station is the one causing such continued operation. When the operation of the contacts of the station relays is plainly visible to an operator or maintainer, it is unnecessary to provide special indicating lamps.

When the operator notices the registration of the same station for several successive cycles of operation, he may suppress that station by the actuation of the cut-out button COB. There are suitable storing means associated with the button COB so that the operator may actuate this button at any time, irrespective of whether or not the system is progressing through a cycle of operation.

More specifically, the momentary actuation of the cut-out button COB closes a pick-up circuit for the storing relay S from through a circuit including the back point of cut-out button COB, windings of relay S, to As soon as the contacts of the relay S have responded to this energization, a stick circuit is closed from through a circuit including back contact I58 of relay 28, front contact |5l of relay S, windings of relay S, to

In order to prolong the first impulse on the control line circuit, it is necessary that the relay S be picked up prior to the picking up of the contacts of the relay SA. If this is not done, the relay S is maintained energized through its stick circuit until the beginning of the next cycle of '75 2,062,710 operation, and is then effective 'to ;prolong the first impulse of that cycle.

Assuming that the relay SA is still deenergized upon the picking up of the contacts of the relay S, the pick-up circuit of the relay SA is open at back contact 38, so that the initiation of the system by. the relay ME in response to that field station which is repeatedly calling, causes the relays FC and D to place a negative impulse upon the control line circuit, but the line circuit is not opened by the relay E until after the response of the relays SA and VP.

With the pick-up circuit of the relay SA opened, and the relay SA deenergized, an energizing circuit is closed for the thermal element I52 of the time element relay TE from through a circuit including back contact 44 of relay SA, back contact I53 of relay 2S, thermal element I52, front contact I54 of relay S, to This energization of the thermal element I52 causes the contacts 39 and I55 to be moved to right-hand positions in accordance with the slow acting characteristics of the thermal time element relay TE.

The closure of contact I55 in a right-hand position closes an obvious pick-up circuit for the upper winding of the relay 2S. The response of the contacts of this relay 28 opens the energizing circuit for the thermal element I52 and closes its stick circuit from through a circuit including back contact 44 of relay SA, front contact I53 of relay 2S, lower winding of relay 2S, to

The picking up of the contact I50 of relay 28 opens the stick circuit of the relay S and its contacts drop away.

The deenergization of the thermal element I52 .allows the contacts of time element relay TE to move to their-left-hand positions in accordance with the slow acting characteristics of the relay. When the contact 39 of time element relay TE is closed, the pick-up circuit of the relay SA is established, as previously pointed out, because the storing relay S has been deenergized.

In brief, the usual application of the first impulse to the control line circuit is prolonged by a period of time including the heating time of the thermal time element TE, the pick-up time of the relay 2S, and the cooling time of the thermal time element relay TE.

Following the pick-up of the relay SA, impulses are applied to the line circuit in the usual manner.

At the field station during this prolonged first impulse on the control line circuit, the time element relay TE measures off its time which is shorter than the long impulse and causes the suppression of the indication station, which in this case is the second group of indications at the station illustrated (see Fig. 3), so that any a of the other indication stations and field locations of more inferior standing may properly transmit their indications.

For example, as soon as the relay LO at that field station is picked up, an energizing circuit for the thermal element is closed from through a circuit including front contact 8| of relay LO, back contact I22 of relay IV thermal element I56 of time element relay TE, back contact I5? of relay 2S to Although this circuit is closed each time this field station transmits indications, the usual time required to initiate the system and cause the first stepping relay I V to be picked up and open this energizing circuit, is insufiicient to allow the contacts I58 and I 59 of the thermal time element relay TE to be completely actuated to their right-hand positions. However, in this case where the first impulse on the control line circuit is prolonged by the thermal time element relay TE in the control office, there is sufficient time for the contacts I58 and I59 of the relay IE to be actuated to right-hand positions.

This closes a pick-up circuit for the stick relay 28 from through a circuit including front contact SI of relay LO, back contact I22 of relay IV contact I59 of relay TE in a right-hand position, windings of the relay 2S to As soon as the contacts of the relay 2S have responded, a stick circuit is closed from through a circuit including front contact 8| of relay LO, back contact I22 of relay IV thermal element I56 of relay TE in a right-hand position, front contact I51 of relay 2S windings of relay 28 to The current in this stick circuit for the relay 28 is of such a small value as to be ineffective to materially eifect the cooling of the thermal element.

As the first impulse on the control line circuit is prolonged, there is suificient time for the heating element of the thermal time element relay Th to cool, so that itscontacts I58 and I59 return to their normal positions upon the opening of back contact I51 of relay 2S As soon as the contact I58 of relay TE reaches its left-hand contacting position, a pick-up circuit is closed for the relay ZSU from through a circuit including contact I58 of relay TE in a left-hand position, front contact I60 of 25 front contact I6I of relay 2L, windings of 2SU, to As soon as the contacts of the relay 2SU have responded, a stick circuit is closed from through a circuit including back contact I62 of stop relay SR, bus wire I63, front contact I64 of relay 2SU, windings of the relay. 2SU, to

It should be noted, that, if the first group of indications is the one that initiated the system from this location, then the lock relay IL would be the one which was energized and. the suppression relay ISU would be energized through front contact I65. In either event, the picking up of the suppression relay or cut-out relay causes the corresponding lock relay to be deenergized, and also controls its pick-up circuit, as to prevent it from again being picked up.

For example, the picking up of the relay ZSU opens the stick circuit of the relay 2L and causes its contacts to drop awayby reason of open back contact 86; while the closure of front contact 8|] continues the pick-up circuit of the lock relays to the next group of indications irrespective of whether the relay 20H is' energized or deenergized. In other words, with the relay ZCI-I energized and front contact I9 closed, the circuit continues on through wire I66 to the heel of a contact on the next change relay, such as a relay 3CH (not shown). Similarly, if the relay 2CI-I is de-energized, a circuit is closed through its back contact I9 and front contact 80 of relay 2SU, to wire I66, and similarly to the next, group of indications.

As this picking up of the suppression relay, such as relay 2SU, causes the de-energization of the corresponding lock relay, such as relay 2L, prior to the picking up of the first stepping relay, such as relay IV there is no code impulse applied to the indication line circuit and .there is no field station registered .in the control ofiice .for that cycle of operation, but the system continues to take its predetermined number of steps and then enters its period of rest.

If the circumstances are such that the remaining indication groups at the station have their change relays deener-gized, so that continued calls are made, then the second actuation of the cut-out button COB causes the next group in order at that station to be suppressed. This suppression of groups may be carried on until all groups at a station have been cut-out.

It is rather obvious that if it was some other field station besides the one illustrated in Fig. 3, that caused the initiation of the system, it would be the one which would be suppressed, (or a group of indications therein) and such a consideration will not be pointed out in detail.

Release of manual suppression-For one reason or other, it might happen that the operator might wish to try out the suppressed station to see if the undesired condition had eliminated itself. In order to do this, it is necessary that means be provided which will allow or cause the dropping out of the suppression relay or relays at a field station. Also, it might happen that for some reason a field station would be undesirably suppressed, and in such cases it is necessary that means he provided to release such a station.

In accordance with the present invention, the transmission of a stop route code is employed for releasing the suppression of a field station. In other words, the positioning of the signal lever SGL in a center at-stopposition followed by the actuation of the starting button SB causes the transmission of a stop control to a selected field station, as previously explained. This momentarily energizes the signals at stop relay, such as relay SR (see Fig. 2), which puts the signals at stop at that station and also causes the restoration of the suppression relay or relays to normally ineffective positions. Assuming that the relay SR. is momentarily energized, the stick circuits for all of the cut-out or suppression relays, such as relays ISU and ZSU for example, are opened at back contact I62. In this way, any particular field station may be selected with the signal lever in a stop position, which picks up the stop relay at that station and drops out the suppression relays.

The restoration of the relay ZSU, for example, allows the lock relay 2L to be controlled in the usual manner, as previously explained, allowing this field station and indication station included therein to transmit its indications.

Summary The present invention provides means whereby the prolongation beyond the normal operating time of the first impulse of a series of control impulses causes the suppression or the cutting out of that field station which is at that time endeavoring to transmit a series of indication impulses. A system of this type accomplishes the desired suppression of a field station without the usual step-by-step operation of the apparatusin the control ofiice and at the field station so that in the event of a failure of a step-by-step mechanism that station may even then be suppressed. In other words, it is only necessary that the control line circuit and the indication line circuit be completed in order to suppress afield station which is undesirably efiecting initiations of the normally at rest system.

The suppression of field stations is accomplished by the addition of simple electro-magnetic relays and simple thermal time relays at the control oflice and at each field station.

The system of the present invention further provides means whereby a field station may be divided into groups for the transmission of a large number of indications so that only one group may transmit during a particular cycle of operation together with means associated with each group for the suppression or cutting out of each group individually rather than the field station location as a whole.

Various other features of the present invention reside in the novel circuit arrangements to accomplish the proper functioning of a system of the character disclosed.

Having thus described a centralized trafiic controlling system as one embodiment of the present invention, it is desired to be understood that this form is selected to facilitate in the disclosure of the invention rather than to limit the number of forms which it may assume; and, it is to be further understood that various modifications, adaptations and alterations may be applied to the specific form shown to meet the requirements of practice, without in any manner departing from the spirit or scope of the present invention except as limited by the appended claims.

What I claim is:

1. In a selective type control system, a control office, a field station, a selective type communication system connecting said control office and said field station, said system being normally inactive, means at said field station for automatically initiating the system into action within a predetermined period of time subsequent to a change at said field station, cut-out means at said field station for preventing the active operation of said system in response to said initiating means until manually restored when the response of said system is delayed for more than said predetermined time, and means for delaying the response of said system to said automatic initiating means.

2. In a selective type control system, a control office, a plurality of field stations, a selective type communication system for connecting said control ofiice and said field stations, said system being normally inactive, means at each field station for automatically initiating the system into active operation within a predetermined time subsequent to a ch n e at thestation for the transmission of indications from that station, cutout means at each field station effective until manually restored to prevent the transmission of indications fro-m that particular field station which initiates the system when more than a predetermined time is required for the initiation, and means in the control office for at times prolonging the time of initiation for more than said predetermined time.

3. In a selective type control system, a control ofiice, a plurality of field stations, a selective type communication system for connecting said control ofiice andsaid field stations, said system being normally inactive, initiating means at the control oifice for causing the application of a series of impulses on the control line circuit with each impulse being applied for a predetermined time, manually operable means at the control ofiice for causing the operation of said initiating means, automatically operable means at each field station for causing the operation of said initiating means in the control ofilce, means in the control office for at times prolonging the application of the first impulse of said series of impulses for more than said predeterminedtime, and cut-out means at each field station for rendering said automatically operable means at such station ineffective when said cut-out means is actuated, said cut-out means being efiectively actuated at that particular field station automatically actuating said initiating means when said first impulse is applied for more than said predetermined period of time.

4. In a selective type control system, a control office, a plurality of field stations, a control line circuit connecting said control ofiice and said field stations, an indication line circuit connecting said control oifice and said field stations, transmitting means for impressing a plurality of different series of current impulses on said control line circuit, indication transmitting means at each field station for impressing a plurality of different series of current impulses on said indication line circuit cut-out means at each field station for rendering said indication transmitting means inefiective when said cut-out means is actuated, lock-out means for allowing the indication transmitting means at only one station at a time to be efiective to transmit during any one series of impulses on said control line circuit, and means effective to actuate said cut-out means at that particular station rendered effective by said lock out means only when the first impulse of a series on said control line circuit is of a particular character.

5. In a selective type control system, a control ofiice, a plurality of field stations, a control line circuit connecting said control ofice and said field stations, an indication line circuit connecting said control office and said field stations, transmitting means for impressing a plurality of different series of current impulses on said control line circuit, indication transmitting means at each field station for impressing a plurality of different series of current impulses on said indication line circuit, cut-out means at each field station for rendering said indication transmitting means ineffective when said cut-out means is actuated, lock-out means for allowing the indication transmitting means at only one station at a time to be effective to transmit during any one series of impulses on said control line circuit, means effective to actuate said cutout means at that particular station rendered efiective by said lock-out means only when the first impulse of a series on said control line circuit is of a particular character, and manually operable means in the control ofiice for determining the character of the first impulse of each series impressed on the control line circuit.

6. In a selective type control system, a control ofiice, a field station. an indication line circuit connecting said control ofiice with said field station, means at said field station for transmitting any one of a plurality of code calls, lock-out means for predetermining which particular code call may be transmitted for any one operation, and manually operable means for selectively preventing until manually reset the transmission of any predetermined one and only that one of said code calls as predetermined by said lock-out means.

7. In a selective type control system, a control ofiice, a field station, an indication line circuit connecting the control ofiice with said field station, means at said field station for transmitting any one of a plurality of code calls, code determining means for selecting which particular code call of said plurality of code calls shall be transmitted for any one operation, and means governed from the control oifice for preventing'until manually reset the transmission of only that particular code which would normally be automatically transmitted as selected by said code determining means but'allowing the transmission of any other code determined by said code determining means.

- 8. In combination, a plurality of groups of devices, a change relay for each group of devices for registering a change in any device of that group, means for controlling each change relay when any device of its group changes its conditions, a lock relay for each of said change relays, a code sending apparatus rendered effective'when a lock relay is energized, means for energizing each lock relay when its corresponding change relay is controlled but preventing more than one look relay from being energized at any one time,

means for measuring off a predetermined period of time each time a lock relay is energized, means for preventing said code sending means from being rendered effective by a lock relay unless it responds within said predetermined period of time, and means selectively governing the time of response of saidcode sending means.

9. In combination, a cycle demarcating relay;

, demarcating relay, a back contact of said lock stick relay, a front contact of each preceding change relay and a back contact of its corresponding change relay; a stick circuit for each lock relay including a back contact of said lock relay and a back contact of said step-by-step means, windings of said lock stick relay, a back contact of each preceding lock relay; and a pick-up circuit for each change relay including a front contact of said lock relay, a front contact of said step-by-step means, and a front contact of its corresponding lock relay.

10. In a selective type control system, a control office, a plurality of field stations, a selective type communication system connecting said control office and said field stations and operable through cycles of operation when initiated, means at each field station for automatically initiating the system into operation within a predetermined time subsequent to a change in indication conditions at its station for the transmission of indications from that station, cut-out means at each field station continuously eifective until reset to prevent the transmission of indications from that particular field station which initiates the system when more than a predetermined time is required for the initiation of the system subsequent to a change in its indication ,conditions,

means in the control office for at times prolong-v ing the time required for initiation for more than said predetermined time, and means manually controllable from the control office for resetting said cut-out means at any selected station on any selected subsequent cycle of operation of said selective type communication system.

11. In a selective type control system, a control office, plurality of field stations, a selective type communication system including line circuit means for connecting said control ofiice and said field stations and said system being operable through cycles of operation when initiated, initiating means at the control office for causing the application of an impulse on the line circuit means during a predetermined period of time at the beginning of each cycle of operation, automatically operable means at each field station for causing the operation of said initiating means in the control oifice, means in the control ofiice for at times prolonging the application of said impulse, cut-out means at each field station for cutting out the associated automatically operable means, and means effectively actuating said outout means at that particular field station automatically actuating said initiating means when said impulse is applied for more than said predetermined period or" time.

12. In a selective type control system, a control office, a plurality of field stations, two line circuits connecting said control office and said field stations, code transmitting means at said control office for transmitting any one of a plurality of codes over one of said line circuits, code receiving means at each field station responsive to the codes transmitted from said control ofiice, code transmitting means at each field station for transmitting simultaneously with said control flice transmitting means any one of a plurality of codes over the other of said line circuits, code receiving means at said control office for receiving the code transmitted from said field stations, means at each field station for preventing the transmission of a particular code to be transmitted from that station when the first element of a code transmitted from said control office is of aparticular character, and means manually governed in the control oifice for selecting the character of the first element of each code transmitted from said control ofiice.

-13. In a selective type control system, a control ofiice, a plurality of field stations, a control line circuit connecting said control ofiice and said field stations, an indication line circuit conmeeting said control oifice and said field stations, control transmitting means at the control office for impressing a plurality of different series of impulses on said control line circuit, indication transmitting means at each field station for impressing a plurality of diirerent series of current impulses on said indication line circuit, cut-out means at each field station for rendering said indication transmitting means at that station ineffective when said cut-out means is'actuated,

lock-out means for allowing the indication trans.

mitting means at only one station at a time to be efiective to transmit during any one series of impulses on said control line circuit, and means effective to actuate said cut-out means at that particular station rendered efiective by said lockout means when the first impulse of a series on said control line circuit is of a particular character.

l4. In a selective type control system, a control ofiice, a plurality of field stations, line circuit means connecting said control ofiice and said field stations, control transmitting means at the control office for impressing a plurality of different series of code elements on said line circuit means, indication transmitting means at each field station for impressing a plurality of difierent series of code elements on said line circuit means simultaneously with said control transmitting means, cut-out means at each field station for rendering said indication transmitting means at that station inefiective when said outout means is actuated, lock-out means for allowing the indication transmitting means at only one station at a time to be efiective to transmit, and means effective to actuate said cut-out means at that particular field station rendered efiective to transmit by said lock-out means when the first code element of. a series transmitted by said control transmitting means is of a particular charactor.

15. In a selective type control system, a selective type communication system connecting a control ofiice and a plurality of field stations and operable through cycles of operation when initiated, means in the control office for initiating said system into a cycle of operation, means at each field station for automatically initiating the system into a cycle of operation, manually operable means for at times delaying the continuance of a cycle of operation already initiated irrespective of whether such cycle was initiated by the control ofiice initiating means or the field station initiating means, means at each field station responsive to a delayed cycle of operation if that station has indications ready to transmit on such cycle of operation to thereby prevent the transmission of such indications.

16. In a selective type control system connecting a control office and a plurality of field stations, said system being operable through cycles of ope-ration when initiated, means at each field station for initiating the system into operation within a predetermined time subsequent to a change in indication conditions at that station for the transmission of such indications to the control ofiice, a cut-out relay at each field station effective when picked up for preventing the transmission of indications from that station, means at each station for picking up said cut-out relay at that station when more than said predetermined time expires before the initiation of said system when that station is ready to transmit, a stick circuit at each field station for its said cut-out relay, means at the control office for at will causing more than said predetermined time to expire for the initiation of the system, and means for at times opening said stick circuit at any particular field station.

1'7. In a selective type control system connecting a control ofiiee and a plurality of field stations, said system being operable through cycles of operation when initiated, means at each field station for initiating the system into operation within a predetermined time subsequent to a change in indication conditions at that station for the transmission of such indications tothe control ofiice, a cut-out relay at each field station efiective when picked up for preventing the transmission of indications from that station, means at each station for picking up said cut-out relay at that station when more than said predetermined time expires before the initiation of said system when that station is ready to transmit, a stick circuit at each field station for its said cut-out relay, means for at will causing more than said predetermined time to expire for the initiation of the system, code responsive means at each field station for opening said stick circuit for said cut-out relay at that field station, and means manually controlled for at will transmitting a code for said code responsive means at any desired station.

18. In a selective type control system, a control line circuit connecting a control office and a plurality of field stations, control transmitting means in the control office for impressing difierent series of impulses on said control line circuit, control receiving means at each field station responsive to said different series of impulses on said line circuit, an indication line circuit connecting the control ofiice and the plurality of field stations, indication transmitting means at each field station for at times impressing a series of impulses on said indication line circuit for each series on said control line circuit, lock-out means at each field station for allowing the indication transmitting means at only one of the field stations to be efiective to transmit during any one series of impulses on said control line circuit, indication receiving means at the control oifice for each of the field stations, cut-out means at each field station for rendering said indica-' tion transmitting means at that station ineffective when the first impulse on said control line circuit is of a particular character only if said lock-out means at that station is conditioned to allow said indication transmitting means at that station to transmit, whereby a monopolizing field station indication transmitting means can be out out without the operation of a control receiving means at such station, and means at each field station for restoring said cut-out means at that station when a particular control is received by said control receiving means at that station.

19. In a selective type control system, an indication line circuit extending between a control ofiice and a plurality of field stations, indication transmitting means at each field station for at times impressing a series of impulses on said indication line circuit, lock-out means at each field station for allowing the indication transmitting means at only one of the field stations to be effective to transmit at any one time, a control line circuit extending between the control ofilce and the plurality of field stations, cut-out means at each field station for preventing the operation of said indication transmitting means at that station until restored, said means being rendered efiective when an impulse of a particular character is impressed on said control line circuit during the conditioning of said indication transmitting means to transmit at that station by said lock-out means at that station, and means at each field station for restoring said cut-out means at that station when a series of impulses is impressed on said control line circuit which series is characteristic of that station.

20. In a selective type control system, a plurality of groups of devices at a field station, indication transmitting means automatically set into operation when a change occurs in any one or all of said groups of devices, interlocking means for causing the indication of said groups to be transmitted one group at a time and in a predetermined order, a thermal relay set into operation upon a change in said devices to measure a predetermined time, a cut-out relay for each group mitting means within said predetermined time measured by said thermal relay, a stick circuit including a control contact for each of said outout relays, and means for at will opening said control contact to thereby deenergize all of said cut-out relays that have been actuated.

2 1. In combination, a plurality of groups of devices at a single location, a change relay for each group of devices for registering a change in any device of that group, a lock relay icr each of said change relays, a code sending apparatus rendered effective when a lock relay is energized to transmit codes in accordance with the condition of the devices of its group, means for preventing more than one look relay from being energized at any one time, means for measuring oil: a predetermined periodof time each time a lock relay is energized, means for preventing said code sending means from being rendered effective by a lock relay unless said code sending means transmits within said predetermined period of time following the actuation of said lock relay, means rendering said cut-out means eirective unmanually restored, means selectively governmg the time. of response of said code sending means, and means for selectively restoring said cut-out means.

22. In a selective type control system; a control linecircuit connecting a control ofiice with a field station; means at the control ofiice for impressing a plurality of different series of positive and/or negative impulses on said control line circuit, the first impulse of each of said series being of a short or long duration; a stick relay which, when picked up, prevents the application of the first impulse of any series; a manually operable contact for closing a pick up circuit for said stick relay; a thermal relay; means for heating said thermal relay only when said stick relay is picked up; a stick circuit for said stick relay including its own front contact and a contact opened whenever said thermal relay is fully heated, wherebysaid stick relay is picked up only for the heating time of said thermal relay; a back contact on said thermal relay closed only when said thermal relay is cooled and which also prevents the application of the first impulse of any series when open; means at the field station distinctively controlled in accordance with the positive and/or negative character of the first impulse of any series; and other means distinctively controlled when the first impulse of any series is of long duration.

23. In a selective type control system, a control ofiice, a field station, a communication system having an indication circuit connecting the control ofiice and field station and including a pulsing contact at a field station, a step-by-step means at the field station operable through a plurality of steps to comprise a cycle of operation when initiated, a plurality of devices at the field station, indication means operating said pulsing contact during a predetermined number of steps taken by said step-by-step means in accordance with the conditions of said plurality of devices when said indication means is initiated, means for initiating said indication means and said step-bystep means when the condition of any one or all of said plurality of devices changes, cut-out means rendering said pulsing contact permanently unaffected by said indication means until manually reset if said stepping operation does not occur before a predetermined time subsequent to the actuation of said initiating means, and means manually governable for at times preventing said 

